Nature Comm：疟疾的疟原虫喜欢年轻的血细胞

人类更多地接触猕猴疟原虫“诺氏疟原虫”，可能会导致其入侵较老血细胞的能力增强。由于这些寄生虫目前喜欢较年轻的血细胞，所以发表在Nature Communications上的这项研究表明，“诺氏疟原虫”在人体中的毒性及其传播能力今后可能会增强。

Caeul Lim及其同事报告说，“诺氏疟原虫”在人血中生长状况差是由于它喜欢入侵一个年轻亚类的细胞。他们发现，连续接触人血导致该寄生虫的演化及其感染更大范围血细胞的能力增强。这些结果也许可解释在一些人类感染病例中已经出现的高寄生虫含量和疾病严重程度。

作者提出，今后还需要进行研究工作来破解导致适应性的机制，因为这一信息有可能被用来防止这种寄生虫向人群中的进一步传播

Nature Communications, DOI:10.1038/ncomms2612

Expansion of host cellular niche can drive adaptation of a zoonotic malaria parasite to humans

Caeul Lim,Elsa Hansen,Tiffany M. DeSimone,Yovany Moreno,Klara Junker,Amy Bei,Carlo Brugnara,Caroline O. Buckee & Manoj T. Duraisingh

The macaque malaria parasite Plasmodium knowlesi has recently emerged as an important zoonosis in Southeast Asia. Infections are typically mild but can cause severe disease, achieving parasite densities similar to fatal Plasmodium falciparum infections. Here we show that a primate-adapted P. knowlesi parasite proliferates poorly in human blood due to a strong preference for young red blood cells (RBCs). We establish a continuous in vitro culture system by using human blood enriched for young cells. Mathematical modelling predicts that parasite adaptation for invasion of older RBCs is a likely mechanism leading to high parasite densities in clinical infections. Consistent with this model, we find that P. knowlesi can adapt to invade a wider age range of RBCs, resulting in proliferation in normal human blood. Such cellular niche expansion may increase pathogenesis in humans and will be a key feature to monitor as P. knowlesi emerges in human populations.